mors ac reipublicae poena. 'Ac' is explanatory, 'death, (which was) the penalty inflicted by the state.'
remorata est, literally, 'Did death keep them waiting a day longer?' i.e. 'Had they to wait a single day longer for their death?' He means that they were put to death on the same day as that on which the ultimum decretum was passed.
vicesimum diem. He speaks in round numbers. The exact time since Oct. 21 (by the Roman reckoning) was eighteen or nineteen days, according as we fix the date of this speech to Nov. 7 or Nov. 8. See [Introduction, p. 12, note].
interfectum te esse convenit, 'you might well have been put to death.'
patres conscripti. The regular title used in addressing the senate. The traditional explanation of it is as follows. The original senators were called patres (patricians); after the expulsion of the kings 160 new senators were enrolled (partly plebeians); these were called conscripti. Hence the whole body were addressed as patres et conscripti and by abbreviation patres conscripti. But this would seem to require adscripti rather than conscripti, and 'it is possible the senators were originally called patres conscripti to distinguish them from those patres who were not senators.' [Gow's Companion to School Classics, p. 192.]
[§5].
in Etruriae faucibus, at Faesulae (now Fiesole), on the south-west slope of the Apennines, commanding one of the passes into Cisalpine Gaul.
adeo, 'even,' 'actually.' Cf. [1. 9] 'atque adeo de orbis terrarum exitio.'
si te iam, etc. 'Credo,' as usual, marks the sentence as ironical. He might conceivably fear two opposite criticisms on his conduct—
(a) 'ne omnes boni serius factum esse dicant,'